I currently use a Xperia Z3 running Android 5.0.2. I have used the home screen widget since I first got Spotify.
The widget works fine when playing music etc. until I close Spotify from the square button next to the home button. When I do this, the album art, song information and option to continue from where I stopped disappear. This has always been a problem and thanks in advance for any replies.
Please read the guide linked below for details on the most common issues and how to fix them. Usually a clean install is the first step to take and resolves most of the usual issues; the guide details the steps to take to ensure a full 'clean installation' is achieved - This includes checking redundant folders and a REBOOT!
I have the same issue on three different devices, so i cant imagine, that a "clean install" is the solution (especially because one of them is new).
The problem is: If Spotify is in the backgroud, it notifys new songs in the notification bar (the spotify symbol is visible). And after a few minutes, this symbol vanishes and the widgets (spotify widget or third party like Jacks) are stopping.
It seems that Android kicks Spotify and the Spotify App should be able to defend this behaviour.